This invention relates to a solid surface treatment method and an apparatus for practicing the same, and more particularly to a surface treatment method used suitably for the manufacturing of semiconductor elements, capable of carrying out a damage- and contamination-free surface treatment operation at a low temperature, and having high reaction selectivity and anisotropy obtaining ability, and an apparatus for practicing this method.
The known dry surface treatment processes using light include:
(1) A method in which a beam of light is emitted in parallel with a substrate so as to excite gas particles alone. PA0 (2) A method in which a beam of light is applied to a substrate so as to excite the surface thereof.
Since a conventional apparatus for practicing the method (1) employs a light source of a large line width, the speed and direction of movement of the gas particles to be excited cannot be limited. Accordingly, if this method is used, the gas particles having speeds in all directions are excited simultaneously. Therefore, this method cannot be used for a treatment for a surface that is required to be anisotropic. The examples of the techniques for treating a surface that is required to be anisotropic include the vertical etching used to transfer a fine mask pattern to a substrate.
In the method (2), the surface of a substrate is excited with the intense light, so that the reaction of the portion of the substrate upon which the light impinges is promoted. This enables the method to be used to treat a surface requiring to have anisotropy. However, while this method is used, troubles occur, i.e., the substrate is heated and damaged due to the intense light entering the surface thereof.
Thus, in the conventional techniques of this kind, the treating of a surface that is required to have anisotropy cannot be done without accompanying the heating and damaging of the substrate. The techniques relative to the surface treatment techniques of this kind are discussed in the "Applied Physics Letters" 35(2) (1979), pages 175-177.
In the conventional techniques mentioned above, no sufficient consideration is given to the coexistence of their capability of providing an object surface with anisotropy and their capability of obtaining the non-surface-damaging characteristics. In order to provide an object surface with anisotropy, it is necessary that the intense light be applied to the surface of a substrate. This causes the substrate surface to be damaged and heated.